Dose Of Epigallocatechin-3-gallate Research Articles

Abstract A67: The effects of SAHA and EGCG on metastatic potential in triple-negative breast cancer

Abstract Approximately 12% of breast cancers are triple negative, and are nearly two times more common in black women that white women. These cancers have a poorer short-term prognosis than other types due to the lack of targeted therapies. The purpose of this study was to use suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor used to treat cutaneous T cell lymphoma (CTCL), and epigallocatechin-3-gallate (EGCG), a DNA methyltransferase (DNMT) inhibitor found in green tea, to decrease metastatic potential in triple-negative breast cancer (TNBC) cells. SAHA and EGCG were administered singly and in combination to determine if the combination was more efficacious than either compound alone in their effects on cell viability and foci, or colony, formation. RNA and protein analysis was performed to evaluate epithelial versus mesenchymal markers, while scratch tests provided phenotypic evidence of changes in migration capability. We found that the combination of SAHA and EGCG at optimal concentrations of 3 μM SAHA and 5 μM reduced breast cancer cellular viability in an additive manner while this combination had no significant effect on control breast cells. This is a very low dose of EGCG compared to most anticancer studies. The colonies formed by the breast cancer cells decreased in size and number. Interestingly, EGCG administered singly increased colony formation. The combination of SAHA and EGCG also reactivated estrogen receptor alpha (ERα), and decreased the expression of miR-221/222, which are microRNAs involved in migration and invasion. The scratch tests supported these findings, with the breast cancer cells exhibiting a decreased ability to migrate. These findings demonstrate the abilities of combined SAHA and EGCG to decrease metastatic potential through epigenetic mechanisms in TNBC. Citation Format: Kayla Ashlyn Lewis, Trygve O. Tollefsbol. The effects of SAHA and EGCG on metastatic potential in triple-negative breast cancer [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A67.

EGCG: Potential application as a protective agent against grass carp reovirus in aquaculture.

Grass carp reovirus (GCRV) is the primary cause of grass carp haemorrhagic disease. The major catechin in green tea, (-)-epigallocatechin-3-gallate (EGCG), has been found to have anti-GCRV activity in the C.idellus kidney cell line (CIK). The aim of this study was to test the potential application of EGCG as an anti-GCRV agent in aquaculture. Here, we demonstrate that various concentrations (99%, 50% and 35%) of EGCG could inhibit GCRV infectivity. EGCG (50%) + GCRV treatment significantly reduced the number of dead fish at 1-, 2-, 3-, 4 -and 5-day post-challenge compared with the negative control (GCRV challenge without EGCG treatment). The safety of EGCG compound products on cell survival was studied using four fish cell lines; we did not detect a significant change in cell viability within 24hours of EGCG incubation. We also evaluated toxicity and concentrations of malondialdehyde (MDA), glutathione (GSH) and lysozyme (LZM) in the grass carp, and the results showed that even a high dose of EGCG did not induce toxicity. Following EGCG compound injection, the concentration of MDA decreased and the concentration of GSH and LZM increased compared with the control groups. We also detected EGCG concentration in grass carp plasma and kidney using HPLC with electrochemical detection after intraperitoneal injection at a dose of 150mg/kg. The concentration of EGCG in the plasma and kidney reached the highest levels (20μg/ml and 1.5μg/ml) about 12hr after injection and then decreased. Overall, EGCG is a safe, effective product that could inhibit GCRV infection and improve immunoactivity in aquaculture.

High-Resolution Adhesion Kinetics of EGCG-Exposed Tumor Cells on Biomimetic Interfaces: Comparative Monitoring of Cell Viability Using Label-Free Biosensor and Classic End-Point Assays.

A high-throughput label-free resonant waveguide grating biosensor, the Epic BenchTop, was utilized to in situ monitor the adhesion process of cancer cells on Arg-Gly-Asp tripeptide displaying biomimetic polymer surfaces. Using highly adherent human cervical adenocarcinoma (HeLa) cells as a model system, cell adhesion kinetic data with outstanding temporal resolution were obtained. We found that pre-exposing the cells to various concentrations of the main extract of green tea, the (−)-epigallocatechin gallate (EGCG), largely affected the temporal evolution of the adhesion process. For unexposed and low dosed cells, sigmoid shaped spreading kinetics was recorded. Higher dose of EGCG resulted in a complete absence of the sigmoidal character, and displayed adsorption-like kinetics. By using the first derivatives of the kinetic curves, a simple model was developed to quantify the sigmoidal character and the transition from sigmoidal to adsorption-like kinetics. The calculations showed that the transition happened at EGCG concentration of around 60 μg/mL. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide end-point assay, we concluded that EGCG is cytostatic but not cytotoxic. The effect of EGCG was also characterized by flow cytometry. We concluded that, using the introduced label-free methodology, the shape of the cell adhesion kinetic curves can be used to quantify in vitro cell viability in a fast, cost-effective, and highly sensitive manner.

Scientific opinion on the safety of green tea catechins.

The EFSA ANS Panel was asked to provide a scientific opinion on the safety of green tea catechins from dietary sources including preparations such as food supplements and infusions. Green tea is produced from the leaves of Camellia sinensis (L.) Kuntze, without fermentation, which prevents the oxidation of polyphenolic components. Most of the polyphenols in green tea are catechins. The Panel considered the possible association between the consumption of (‐)‐epigallocatechin‐3‐gallate (EGCG), the most relevant catechin in green tea, and hepatotoxicity. This scientific opinion is based on published scientific literature, including interventional studies, monographs and reports by national and international authorities and data received following a public ‘Call for data’. The mean daily intake of EGCG resulting from the consumption of green tea infusions ranges from 90 to 300 mg/day while exposure by high‐level consumers is estimated to be up to 866 mg EGCG/day, in the adult population in the EU. Food supplements containing green tea catechins provide a daily dose of EGCG in the range of 5–1,000 mg/day, for adult population. The Panel concluded that catechins from green tea infusion, prepared in a traditional way, and reconstituted drinks with an equivalent composition to traditional green tea infusions, are in general considered to be safe according to the presumption of safety approach provided the intake corresponds to reported intakes in European Member States. However, rare cases of liver injury have been reported after consumption of green tea infusions, most probably due to an idiosyncratic reaction. Based on the available data on the potential adverse effects of green tea catechins on the liver, the Panel concluded that there is evidence from interventional clinical trials that intake of doses equal or above 800 mg EGCG/day taken as a food supplement has been shown to induce a statistically significant increase of serum transaminases in treated subjects compared to control.

Epigallocatechin Gallate-Mediated Cell Death Is Triggered by Accumulation of Reactive Oxygen Species Induced via the Cpx Two-Component System in Escherichia coli.

The high antimicrobial activity of epigallocatechin gallate (EGCG), the most bioactive component of tea polyphenol with a number of health benefits, is well-known. However, little is known about the mechanism involved. Here, we discovered the relationship between reactive oxygen species (ROS), the Cpx system, and EGCG-mediated cell death. We first found an increase in ampicillin resistance as well as the transcription level of a LD-transpeptidase (LD-TPase) involved in cell wall synthesis; ycbB transcription was upregulated whereas that of another LD-TPase, ynhG, appeared to be constant after a short exposure of Escherichia coli to sub-inhibitory doses of EGCG. Additionally, the transcription level of cpxP, a downstream gene belonging to the Cpx regulon, was positively correlated with the concentration of EGCG, and significant upregulation was detected when cells were treated with high doses of EGCG. Through analysis of a cpxR deletion strain (ΔcpxR), we identified a constant ROS level and a notable increase in the survival rate of ΔcpxR, while the ROS level increased and the survival rate decreased remarkably in the wild-type strain. Furthermore, thiourea, which is an antioxidant, reduced the ROS level and antimicrobial activity of EGCG. Taken together, these results suggest that EGCG induces ROS formation by activating the Cpx system and mediates cell death.

The anti-hyperuricemic effect of epigallocatechin-3-gallate (EGCG) on hyperuricemic mice

Epigallocatechin-3-gallate (EGCG), a major constituent of green tea catechin, has been used for antioxidant. This study aimed to evaluate the antihyperuricemic activity of EGCG on hyperuricemic mice. We demonstrated that serum uric acid (UA) level was decreased significantly with dose-dependence by EGCG treated with 10, 20, and 50mg/kg. Compared with the model, data on blood urea nitrogen (BUN) supported that there was significance with high dose of EGCG (50mg/kg). Levels of serum creatinine (Cr) in each EGCG-treated group were decreased but not significant; the activities of hepatic xanthine oxidase (XOD) and adenosine deaminase (ADA) in high dose groups' EGCG were notably lower than those of model group. EGCG could downregulate the renal mRNA expression levels of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1) on hyperuricemic mice. These results presented that EGCG had obvious hypouricemic and renal protective effects on hyperuricemic mice. Our data may have a potential value in clinical practice in the treatment of hyperuricemia.

Experimental study on the inhibitory effect of epigallocatechin gallate on renal calcium oxalate crystal formation

Objective To compare the effects of different dosages of epigallocatechin gallate (EGCG) in calcium oxalate stone rate, to expolre content differences in malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and calcium oxalate crystal deposition. Methods Fifty rats were randomly divided into 5 groups: normal control group, calcium oxalate kidney stone model group and different doses of EGCG intervention group. The control group was permitted to drink purified water freely; model group was given 2 ml stone liquid that was prepared with 1% ethylene glycol and 2% ammonium chloride by the lavage. In the EGCG intervention groups, daily doses of 0.1% EGCG (10, 30, and 50 mg/kg) were given introgastrically on the basis treatment in the model group. Twenty-eight days later, the rats were sacrificed and the right kidney was prepared into homogenate. The thiobarbituric acid (TBA) method was used for the determination of MDA. The xanthine oxidase method was applied to detect SOD activity. CAT activity was tested by ultraviolet spectrophotometry. The DTNB method was used to determine GSH-Px activity. The left kidney tissue was stained by HE method, and crystal deposition was observed by polarizing microscopy. Results In the blank control group, MDA concentration was (2.74±0.47) μmol/L, SOD activity (541.71±10.61) Nu/g, CAT activity (44.49±3.45) U/g and GSH-Px activity (41.61±2.50)×103 U/g·protein. As compared with the blank control group, MDA concentration of calcium oxalate kidney stones in the model group was increased significantly, while the activity of SOD (332.44±12.01) Nu/g, CAT (32.15±1.99) U/g and GSH-Px (21.36±1.58)×103 U/g·protein was significantly decreased (P=0.009). In the low-dose EGCG group, the activity of SOD, CAT and GSH-Px was (517.41±28.37) Nu/g, (34.42±2.55) U/g and (23.94±2.95)×103 U/g·protein respectively, that in the middle-dose EGCG group (545.04±23.84), (35.42±2.61) and (25.10±2.64) respectively, and that in the high-dose EGCG group (550.58±16.55) Nu/g, (35.40±2.39) U/g and (26.67±1.93)×103 U/g·protein respectively. As compared with the model group, SOD, GSH-Px and CAT actively was increased in the EGCG groups (P=0.005). The calcium oxalate crystal deposition in the renal tissue was negatively correlated with the dose of EGCG interference (r=-0.483, P= 0.008). Conclusion There were significant differences in MDA, SOD and GSH-Px contents in calcium oxalate stone rats treated with different doses of EGCG, which indicated that EGCG could reduce the formation of calcium oxalate kidney stones by reducing the oxidative damage. Key words: Calcium oxalate; Epigallocatechin gallate; Oxidative damage

Anti-skin-aging effect of epigallocatechin gallate by regulating epidermal growth factor receptor pathway on aging mouse model induced by d-Galactose

Epigallocatechin gallate(EGCG) is a monomer separated from tea catechins, as an well-known antioxidant, which helps fight wrinkles and rejuvenate skin cells. In this study, we investigated the anti-aging effect of EGCG, and to clarify underlying mechanism of skin aging in a d-galactose-induced aging mouse model. Forty-five male mice were divided into 5 groups and treated with different dose of EGCG, Vitamin C (VitC) to mice as a positive control. All groups except vehicle were established aging model induced by d-galactose (200mg/kg/day) that was subcutaneously injected to mice for 8 weeks. Two weeks after injection of d-galactose, EGCG and Vit C groups were simultaneously administered once a day by subcutaneously inject after 5h for injecting d-galactose. The results show that EGCG can be absorbed by the skin. Overall, the conditions of the skin of EGCG-treatment groups were improved, the whole structure of skin were better than control groups, and the levels of oxidative stress and the expression of relate with EGFR proteins were significantly higher than control group after EGCG treatment. All these findings suggest that EGCG can resist skin senility effectively. And the EGFR with relate of downstream proteins are implicated in the skin aging.

DOSE-DEPENDENT AMELIORATION OF EPIGALLOCATECHIN-3-GALLATE AGAINST SODIUM VALPROATE INDUCED AUTISTIC RATS

Objective: Autism is a neurodevelopment related disorder with a range of clinical presentations attending serious behavioral and neurological disorders among young children that now occur at epidemic rates in developing countries, India included. The objective of this research was to study the effect of epigallocatechin gallate (EGCG) on sodium valproate-induced autism rats.Methods: On the 12th day of gestation wistar rats were administered with a single intraperitoneal injection of sodium valproate (VPA) (600 mg/kg body weight), which induced autism. The rats were treated with EGCG in varying doses 1, 2 and 5 mg/kg body weight via oral administration. The neuroprotectivity effect of the EGCG was followed by assessing the neurotransmitters and neurobiochemical activities such as serotonin, glutamate and nitrite levels in hippocampus and cerebellum region of the brain. Results: Early prenatal exposure to VPA provokes autistic symptoms. Induction of autism significantly impinged the neurotransmitters and neurochemicals such as serotonin, glutamate and nitrite levels in the brain (hippocampus and cerebellum) increased significantly in the rats exposed to VPA. After treatment with an effective dose of EGCG 2 mg/kg body weight the neurotransmitters and neurochemicals levels were decreased when compared with control and VPA-exposed rats. Conclusion: EGCG ameliorates and reverses autistic attributes possibly due to its neuroprotective activity which could pave the way for future investigation for the possible therapeutic approach.

Dose-dependent decrease in mortality with no cognitive or muscle function improvements due to dietary EGCG supplementation in aged mice.

We have previously shown that a diet containing epigallocatechin gallate (EGCG) and beta-alanine is not effective in improving either cognitive or muscle function in aged (18 month) mice (Gibbons et al., Behav. Brain Res., 2014, 272:131-140; Pence et al., Appl. Physiol. Nutr. Metab., 2016, 41(2): 181-190). However, this diet reduced oxidative stress in the brain, and previous studies using longer term interventions and other doses have documented beneficial effects in cognitive and muscle function, especially with EGCG. Here we hypothesized that a different dose of EGCG or longer feeding period would be more efficacious in improving cognition. Aged (21-25 mo) Balb/cByJ male mice underwent 63 days of feeding with EGCG at 0, 0.091, or 3.67 mg/g AIN-93M diet and were then subjected to a battery of cognitive and muscle function tests. EGCG feeding at either of the 2 doses did not alter preference for novel versus familiar arm in the Y-maze test (p = 0.29) and did not affect learning in the active avoidance test (p = 0.76). Similarly, EGCG did not affect preference for novel versus familiar mice in a social discrimination test (p = 0.17). Likewise, there was no effect of EGCG on muscle function by grip strength (p = 0.16), rotarod (p = 0.18), or treadmill test to exhaustion (p = 0.25). EGCG reduced mortality in a dose-dependent fashion (p = 0.05, log-rank test for trend), with 91% of high EGCG, 72% of low EGCG, and 55% of control mice surviving to the end of the study. In conclusion, EGCG improves survival in aged mice but does not affect cognitive or muscle function.

Anti-Fatigue Effect of Green Tea Polyphenols (-)-Epigallocatechin-3-Gallate (EGCG).

Background:(-)-Epigallocatechin-3-gallate (EGCG) is the most abundant of the green tea polyphenols that exhibit a variety of bioactivities. The objective of this study was to evaluate the anti-fatigue effect of EGCG by forced swimming exercise.Materials and Methods:The mice were divided into one control group and three EGCG-treated groups. The control group was administered with distilled water and EGCG-treated groups were administered with different dose of EGCG (50, 100, and 200 mg/kg) by oral gavage for 28 days. On the last day of experiment, the forced swimming exercise was performed and corresponding biochemical parameters were measured.Results:The data showed that EGCG prolonged exhaustive swimming time, decreasing the levels of blood lactic acid, serum urea nitrogen, serum creatine kinase and malondialdehyde, which were accompanied by corresponding increase in liver and muscle glycogen contents, and superoxide dismutase, catalase, and glutathione peroxidase activities.Conclusions:This study indicated that EGCG had an anti-fatigue effect.SUMMARY EGCG significantly prolonged exhaustive swimming time and decreased the levels of BLA, SUN, SCK and MDA, which were accompanied by corresponding increases in liver and muscle glycogen contents, and SOD, CAT, and GPx activities.EGCG can be used to design nutraceutical supplements aimed to facilitate recovery from fatigue and attenuate exhaustive exercise-induced oxidative damage. Abbreviations used: EGCG: (-)-Epigallocatechin-3-gallate, ROS: reactive oxygen species, BLA: blood lactic acid, SUN: serum urea nitrogen, SOD: superoxide dismutase, GPx: glutathione peroxidase, CAT: catalase, SCK: serum creatine kinase, MDA: malondialdehyde, C: control, LET: Low-dose EGCG-treated, MET: Middle-dose EGCG-treated, HET: High-dose EGCG-treated, GTE: green tea extract.

Epigallocatechin-3-gallate counters cisplatin toxicity of rat testes

Context: Epigallocatechin-3-gallate (EG), the main active flavonoid in green tea, has well-known anti-inflammatory, antioxidant, and anti-apoptotic activities. Objective: The EG protection against testicular injury induced by cisplatin was studied in Sprague–Dawley rats. Materials and methods: Cisplatin (10 mg/kg, i.p) was given as a single injection to rats. EG was given at 40 and 80 mg/kg/day, i.p., for 5 days, starting the same day of cisplatin insult. Serum testosterone, and testicular malondialdehyde, total antioxidant status, nitric oxide, interleukin-6, interleukin-1β, cytochrome C, Bax/Bcl-2 ratio, and caspase-3 were measured. In addition, testicular histopathological examination and immunohistochemical expression of testicular tumour necrosis factor-α were evaluated. Results: Cisplatin, compared to the control, significantly decreased serum testosterone (6.48 ± 0.7 vs. 50.8 ± 4.91 ng/10 mL), and testicular tissue antioxidant status (17.3 ± 1.21 vs. 64.12 ± 5.4 μmol/g), and significantly increased interleukin-6 (85.81 ± 6.11 vs. 38.2 ± 2.79 pg/100 mg), interleukin-1β (98.09 ± 8.31 vs. 32.52 ± 2.08 pg/100 mg), malondialdehyde (74.5 ± 5.88 vs. 23.8 ± 1.91 nmol/g), nitric oxide (104.98 ± 8.5 vs. 52.68 ± 5.12 nmol/100 mg), cytochrome C (5.97 ± 0.33 vs. 1.6 ± 0.99 ng/mg protein), Bax/Bcl-2 ratio (4.01 ± 0.38 vs. 0.71 ± 0.0), and caspase-3 (3.2 ± 0.21 vs. 0.98 ± 0.08 O.D. 405 nm) in rat testes. EG (40 and 80 mg/kg, respectively) caused significant increases of serum testosterone (33.9 ± 2.89 and 47.88 ± 4.4 ng/10 mL), and testicular antioxidant status (47.1 ± 3.92 and 58.22 ± 3.58 μmol/g), and significant decreases of interleukin-6 (57.39 ± 4.2 and 48.18 ± 3.98 pg/100 mg), interleukin-1β (65.12 ± 5.88 and 41.96 ± 3.51 pg/100 mg), malondialdehyde (42.3 ± 3.9 and 28.67 ± 2.49 nmol/g), nitric oxide (70.6 ± 6.79 and 61.31 ± 5.18 nmol/100 mg), cytochrome C (3.4 ± 0.27 and 2.21 ± 0.18 ng/mg protein), Bax/Bcl-2 ratio (1.49 ± 0.14 and 1.1 ± 0.09), and caspase-3 (2.1 ± 0.17 and 1.48 ± 0.13 O.D. 405 nm) in testes of cisplatin-treated rats. Additionally, both doses of EG significantly ameliorated the histopathological injury and reduced tumour necrosis factor-α expression in rat testes. Conclusion: EG can afford testicular protection in cisplatin-challenged rats by its antioxidant, antinitrative, anti-inflammatory and antiapoptotic effects.

A new update for radiocontrast-induced nephropathy aggravated with glycerol in rats: the protective potential of epigallocatechin-3-gallate

Contrast media (CM) is known to have nephrotoxic adverse effects. Epigallocatechin-3-gallate (EGCG) is the most abundant and active catechin in green tea, and has strong antioxidant and anti-inflammatory properties. This study investigated whether EGCG can reduce contrast-induced nephrotoxicity (CIN), alone or with glycerol (GLY)-induced renal damage, and to understand its mechanisms of protection against toxicity, using models of GLY and CIN in rats. The rats were separated into eight groups (n = 6 in each), as follows: Healthy, GLY, CM, GLY + CM, CM + EGCG 50 mg/kg (po), GLY + CM + EGCG 50 mg/kg (po), CM + EGCG 100 mg/kg (po), and GLY + CM + EGCG 100 mg/kg (po). Both doses of EGCG protected against CM-induced renal dysfunction, as measured by serum creatinine and blood urea nitrogen (BUN). In addition, EGCG treatment markedly improved CIN-induced oxidative stress, and resulted in a significant down-regulatory effect on tumor necrosis factor (TNF)-α and nuclear factor (NF)-κB mRNA expression. Moreover, histopathological analysis showed that EGCG also attenuated CM-induced kidney damage. Considering the potential clinical use of CM and the numerous health benefits of EGCG, this study showed the protective role of multi-dose EGCG treatment on CIN and GLY-aggravated CIN through different mechanisms.

Epigallocatechin-3-gallate alleviates paraquat-induced acute lung injury and inhibits upregulation of toll-like receptors

AimsTo evaluate the detoxifying effect of epigallocatechin-3-gallate (EGCG) on paraquat (PQ)-induced acute lung injury in mice, and to explore the action mechanisms. Main methodsFollowing administration of PQ, the mice received a low, a medium or a high dose of EGCG daily for three days. Histopathology of the lungs were examined by H&E staining. The levels of inflammatory cytokines, such as TNF-α, IL-1β and IL-6, in the bronchoalveolar lavage fluid were measured by enzyme-linked immunosorbent assay. Activation of NF-κB was assessed by Western blot and electrophoretic mobility gel shift assay. The expression of toll-like receptor (TLR)-2, 4, 9 and TLR adaptors (MyD88 and TRAF6) was detected by Western blot and immunohistochemical staining. The protective effect of EGCG against PQ toxicity was validated in vitro using A549 lung cancer cell line. Key findingsTreatment with EGCG dose-dependently attenuated PQ-induced acute lung injury in mice by reducing alveolar edema, hemorrhage, inflammatory cell infiltration and production of inflammatory cytokines. EGCG inhibited the activation of NF-κB and the upregulation of TLR 2, 4 and 9 as well as their adaptors MyD88 and TRAF6 in the lungs following PQ challenge. In addition, EGCG significantly reduced PQ-induced cell death, cytokine production, activation of NF-κB, and upregulation of TLRs and adaptors in A549 cells. SignificanceOur data suggest that TLR-mediated activation of NF-κB in the non-immune pulmonary cells could be involved in PQ-induced acute lung injury, and it may serve as a target of EGCG against PQ pulmonary toxicity.

Resveratrol and Epigallocatechin-3-gallate addition to thawed boar sperm improves in vitro fertilization

Thawing is one of the most delicate process after semen cryopreservation as spermatozoa pass from a dormant metabolic stage to a sudden awakening in cellular metabolism. The rapid oxygen utilization leads to an overproduction of reactive oxygen species that can damage sperm cells, thus causing a significant decrease of fertilizing potential of frozen-thawed spermatozoa. Resveratrol (Res) is a natural grape-derived phytoalexin and Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea (Camellia sinensis); both molecules are known to possess high levels of antioxidant activity. The objective of the present study was to assess the effect of different concentrations of Res (0.5, 1 or 2 mM; Experiment 1) or EGCG (25, 50 or 100 μM; Experiment 2) supplementation to thawing boar semen extender on sperm quality parameters (viability and acrosome integrity) and in vitro fertilization (IVF). Semen after thawing and dilution with three volumes of Beltsville Thawing Solution (BTS), was immediately divided in control group without antioxidants addition (CTR) and either Res or EGCG groups. Sperm viability and acrosome integrity were evaluated in CTR, Res or EGCG groups after 1 h of incubation at 37 °C. The addition of different doses of Res or EGCG to thawing extender for 1 h did not induce any effect on boar sperm viability and acrosome integrity. However, both Res and EGCG treated samples exhibited a significantly higher penetration rate compared with CTR when used for IVF. In particular the treatment with all the EGCG concentrations increased the penetration rate (P < 0.01) while only Res 2 mM induced a significant increase of this parameter (P < 0.01). In addition, EGCG 25 and 50 μM supplementation significantly increased total fertilization efficiency as compared to control (EGCG 25 μM: 40.3 ± 8.2 vs 26.8 ± 9.5, P < 0.05; EGCG 50 μM: 40.4 ± 7.8 vs 26.8 ± 9.5, P < 0.01). The same effect was observed with Res 2 mM (51.0 ± 7.6 vs 29.6 ± 11.3, P < 0.01). In conclusion, our results indicate that the addition of different doses of the two antioxidants to thawed spermatozoa for one hour, even if does not exert any effect on sperm viability and acrosome integrity, efficiently improves in vitro penetration rate. Moreover, both molecules (EGCG 25 and 50 μM and Res 2 mM) significantly increases the total efficiency of fertilization.

Epigallocatechin-3-gallate enhances key enzymatic activities of hepatic thioredoxin and glutathione systems in selenium-optimal mice but activates hepatic Nrf2 responses in selenium-deficient mice

Selenium participates in the antioxidant defense mainly through a class of selenoproteins, including thioredoxin reductase. Epigallocatechin-3-gallate (EGCG) is the most abundant and biologically active catechin in green tea. Depending upon the dose and biological systems, EGCG may function either as an antioxidant or as an inducer of antioxidant defense via its pro-oxidant action or other unidentified mechanisms. By manipulating the selenium status, the present study investigated the interactions of EGCG with antioxidant defense systems including the thioredoxin system comprising of thioredoxin and thioredoxin reductase, the glutathione system comprising of glutathione and glutathione reductase coupled with glutaredoxin, and the Nrf2 system. In selenium-optimal mice, EGCG increased hepatic activities of thioredoxin reductase, glutathione reductase and glutaredoxin. These effects of EGCG appeared to be not due to overt pro-oxidant action because melatonin, a powerful antioxidant, did not influence the increase. However, in selenium-deficient mice, with low basal levels of thioredoxin reductase 1, the same dose of EGCG did not elevate the above-mentioned enzymes; intriguingly EGCG in turn activated hepatic Nrf2 response, leading to increased heme oxygenase 1 and NAD(P)H:quinone oxidoreductase 1 protein levels and thioredoxin activity. Overall, the present work reveals that EGCG is a robust inducer of the Nrf2 system only in selenium-deficient conditions. Under normal physiological conditions, in selenium-optimal mice, thioredoxin and glutathione systems serve as the first line defense systems against the stress induced by high doses of EGCG, sparing the activation of the Nrf2 system.

Epigallocatechin-3-gallate augments therapeutic effects of mesenchymal stem cells in skin wound healing.

In non-healing wounds, mesenchymal stem cell (MSC)-based therapies have the potential to activate a series of coordinated cellular processes, including angiogenesis, inflammation, cell migration, proliferation and epidermal terminal differentiation. As pro-inflammatory reactions play indispensable roles in initiating wound repair, sustained and prolonged inflammation exhibit detrimental effects on skin wound closure. We investigated the feasibility of using an antioxidant agent epigallocatechin-3-gallate (EGCG), along with MSCs, to improve wound repair through their immunomodulatory actions. In a rat model of wound healing, a single dose of EGCG at 10mg/kg increased the efficiency of MSC-induced skin wound closure. Twenty days after the wound induction, MSC treatment significantly enhanced the epidermal thickness, which was further increased by EGCG administration. Consistently, the highest extent of growth factors upregulation for neovascularization induction was seen in the animals treated by both MSCs and EGCG, associated with a potent anti-scarring effect throughout the healing process. Finally, expression levels of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6, in the wound area were reduced by MSCs, and this reduction was further potentiated by EGCG co-administration. EGCG, together with MSCs, can promote skin wound healing likely through their combinational effects in modulating chronic inflammation.

A new update for radiocontrast induced nephropathy aggravated with glycerol in rats: The protective potential of epigallocatechin-3-gallate

AbstractContrast media (CM) is known to have nephrotoxic adverse effects. Epigallocatechin-3-gallate (EGCG) is the most abundant and active catechin in green tea, and has strong antioxidant and anti-inflammatory properties. This study investigated whether EGCG can reduce contrast-induced nephrotoxicity (CIN), alone or with glycerol (GLY)-induced renal damage, and to understand its mechanisms of protection against toxicity, using models of GLY and CIN in rats. The rats were separated into eight groups (n = 6 in each), as follows: Healthy, GLY, CM, GLY + CM, CM + EGCG 50 mg/kg (po), GLY + CM + EGCG 50 mg/kg (po), CM + EGCG 100 mg/kg (po), and GLY + CM + EGCG 100 mg/kg (po). Both doses of EGCG protected against CM-induced renal dysfunction, as measured by serum creatinine and blood urea nitrogen (BUN). In addition, EGCG treatment markedly improved CIN-induced oxidative stress, and resulted in a significant down-regulatory effect on tumor necrosis factor (TNF)-α and nuclear factor (NF)-κB mRNA expression. Mor...

EGCG, a green tea catechin, attenuates the progression of heart failure induced by the heart/muscle-specific deletion of MnSOD in mice

BackgroundManganese superoxide dismutase (MnSOD) is an important antioxidant enzyme affected in heart/muscle-specific MnSOD-deficient mice (H/M-SOD2−/−), which develop progressive congestive heart failure and exhibit pathology typical of dilated cardiomyopathy. MethodsIn this study we investigated the beneficial effects of epigallocatechin gallate (EGCG) on the cardiac remodeling and telomere biology in H/M-SOD2−/− mice. H/M-SOD2−/− mice were divided into three groups: those receiving normal drinking water (KO), a low dose of EGCG (L: 10mg/L), and a high dose of EGCG (H: 100mg/L) beginning at eight weeks of age and lasting for eight weeks. ResultsThe mice in the KO group exhibited significantly dilated cardiac remodeling with reduced contractility, which was prevented by the administration of EGCG. Although the mortality of KO mice was about 50% at 16 weeks of age, the mice that received EGCG had a high survival rate. The cardiac dilatation with reduced cardiac contraction in KO mice was prevented by EGCG treatment. The levels of myocardial oxidative stress and free fatty acids were lower in the group treated with EGCG compared with the KO group. The increased expression of nitric oxide synthase 2, nitrotyrosine, fatty acid synthase, Toll-like receptor 4, and Sirt1 in the KO mice were prevented by EGCG treatment. The shortening of the telomere length, decreased telomerase activity in KO mice were also prevented by EGCG. ConclusionsH/M-SOD2−/− mice receiving EGCG have a lower mortality rate and exhibit less inflammation and a better preserved cardiac function and telomere biology.

Synergistic Effect of Artificial Tears Containing Epigallocatechin Gallate and Hyaluronic Acid for the Treatment of Rabbits with Dry Eye Syndrome.

Dry eye syndrome (DES) is a common eye disease. Artificial tears (AT) are used to treat DES, but they are not effective. In this study, we assessed the anti-inflammatory effect of AT containing epigallocatechin gallate (EGCG) and hyaluronic acid (HA) on DES. Human corneal epithelial cells (HCECs) were used in the WST-8 assay to determine the safe dose of EGCG. Lipopolysaccharide-stimulated HCECs showing inflammation were treated with EGCG/HA. The expression of IL-1ß, IL-6, IL-8, and TNF-α was assessed by real-time PCR and AT physical properties such as the viscosity, osmolarity, and pH were examined. AT containing EGCG and HA were topically administered in a rabbit DES model established by treatment with 0.1% benzalkonium chloride (BAC). Tear secretion was assessed and fluorescein, H&E, and TUNEL staining were performed. Inflammatory cytokine levels in the corneas were also examined. The non-toxic optimal concentration of EGCG used for the treatment of HCECs in vitro was 10 μg/mL. The expression of several inflammatory genes, including IL-1ß, IL-6, IL-8, and TNF-α, was significantly inhibited in inflamed HCECs treated with 10 μg/mL EGCG and 0.1% (w/v) HA (E10/HA) compared to that in inflamed HCECs treated with either EGCG or HA alone. AT containing E10/HA mimic human tears, with similar osmolarity and viscosity and a neutral pH. Fluorescence examination of the ocular surface of mouse eyes showed that HA increased drug retention on the ocular surface. Topical treatment of DES rabbits with AT plus E10/HA increased tear secretion, reduced corneal epithelial damage, and maintained the epithelial layers and stromal structure. Moreover, the corneas of the E10/HA-treated rabbits showed fewer apoptotic cells, lower inflammation, and decreased IL-6, IL-8, and TNF-α levels. In conclusion, we showed that AT plus E10/HA had anti-inflammatory and mucoadhesive properties when used as topical eye drops and were effective for treating DES in rabbits.